Drilling operations subject drill pipe to a variety of stresses, frictional forces, and environments. During directional drilling, the drill pipe will bend, resulting in well bore contact. As a result, the center portion of the drill pipe will wear and ultimately lead to failure or premature replacement of the drill pipe. The terms drill pipe and standard weight drill pipe are referred to interchangeably herein.
To alleviate some of the damage produced during directional drilling, wear pads may be installed at select locations on the drill pipe. Wear pads presently used with standard weight drill pipe are generally cylindrical, sleeve-like devices installed on the exterior surface of the drill pipe. Many of these sleeve-like wear pads clamp to the exterior surface of the drill pipe. Unfortunately, clamp style wear pads tend to slip leaving target wear prone areas exposed. Additionally, the necessary installation and subsequent maintenance of clamp style wear pads will slow down drilling operations.
Standard weight drill pipe has mechanical properties such as flexibility, toughness, and fatigue resistance, among others that make it particularly suitable for use in the center of a drill string. A particular drill string may include a variety of components, such as drill collars and intermediate weight members, which are typically used between the drill bit and the drill pipe in the drill string. These components are made of thicker, stiffer, heavier materials than standard weight drill pipe. Accordingly, drill collars and intermediate weight members are used as a transition from drill bit to drill pipe in order to reduce impact loads on the drill pipe. Since at least 1960, drill collars and intermediate weight members have been available with machined wear pads. However, drill collars and intermediate weight members do not have the stated mechanical properties of drill pipe. Additionally, these heavier components use a greater amount of limited drill rig power and lack flexibility. Other limitations prevent drill collars and intermediate weight members from functioning as a feasible alternative to drill pipe and the wear pads mentioned above.
Although currently available wear pads for standard weight drill pipe provide some protection and functionality, improvements are desired by the industry. The industry desires increased performance and reduced maintenance at the well site in order to enhance safety and minimize operational costs.